To better understand prostate cancer, it helps to understand what the prostate is. The prostate is a gland found only in males, and is located in front of the rectum and below the urinary bladder. The size of the prostate varies with age. In younger men, it is about the size of a walnut, but it can be much larger in older men. The job of the prostate is to produce semen—the fluid that nourishes and protects sperm. Prostate cancer is cancer in a small walnut-sized gland called the prostate.
Prostate cancer is one of the most common cancers in men, affecting about 1 in 7 men at some time in their lives. Prostate cancer is rare before age 40, and most common in men over 65. More than 2 million men in the United States are prostate cancer survivors.
Prostate cancer tends to grow slowly and can usually be treated successfully, but it can be very serious if it is not found before it spreads.